Question

an object is placed 21 cm in front of a concave mirror with a focal length of 14 cm, what is the image position?

Answer 1

42 cm

Step-by-step explanation:

We can solve the problem by using the lens/mirror equation:

`(1)/(f)=(1)/(p)+(1)/(q)`

where

f is the focal length of the mirror

p is the distance of the object from the mirror

q is the distance of the image from the mirror

In this problem, we have

f = +14 cm is the focal length of the mirror (positive for a concave mirror)

p = 21 cm is the distance of the object

Solving for q, we find the distance of the image:

`(1)/(q)=(1)/(f)-(1)/(p)=(1)/(14)-(1)/(21)=0.0238 cm^(-1)\\q=(1)/(0.0238)=42 cm`